My dear Children,
... The beginning of this Harvest was very promi[sing]. The crops in general had a very rich appearance, and it was generally expected that next season would be very plentiful. But within the last few weeks the greatest alarm prevails throughout the kingdom. It is dreaded that nothing less than a famine must prevail next summer unless the Almighty lord interpose. A disease seized the potato crop which was the standing food of the Country. The Potatoes which were good and healthy a few days since are now rotten in the Ground. Even some which were dug in beautiful dry weather and stored in Pits seem to be affected with the same blight. The newspapers teem with alarming accounts of the same disease throughout the kingdom. I cannot say whether the loss is equal to the alarm ...
I remain your
Affectionate Father
James Prenderg[ast]

James and Elizabeth Prendergast of Milltown, County Kerry, Ireland, had six children. They dictated letters, including this excerpt postmarked Oct. 25, 1845, to a scrivener and mailed them to their children who had immigrated to Boston. The 48 surviving letters, transcribed and published in The Prendergast Letters: Correspondence from Famine-Era Ireland, 1840-1850, edited by Shelley Barber (University of Massachusetts Press), offer a rare firsthand glimpse of Ireland's Great Famine. They detail the famine's impact on Ireland's residents.

Although you may not have family letters, resources such as these can help you understand what your family might've endured, and explain why some people left Ireland while others stayed. A classic is Cecil Woodham-Smith's The Great Hunger: Ireland: 1854–1849 (Penguin Books). Famine Echoes by Cathal Poirteir (Gill & Macmillan) preserves stories from descendants of famine survivors, recorded in the 1940s as part of Ireland's Folklore Commission. Whether your Irish ancestors left Ireland in the 1600s or the 1920s, Kerby A. Miller's Emigrants and Exiles: Ireland and the Irish Exodus to North America (Oxford University Press) is a hefty tome worth the read.

If you have immigrant ancestors, you are going to want to know how to get a hold of their naturalization records. Find out tricks to tracking them down and analyzing their records to build your genealogy research.